Nirmatrelvir/ritonavir (Paxlovid) has been a game changer for high-risk patients with early COVID-19 symptoms but has significant interactions with commonly used cardiovascular medications, a new paper cautions.
COVID-19 patients with cardiovascular disease (CVD) or risk factors such as diabetes, hypertension, and chronic kidney disease are at high risk of severe disease and account for the lion’s share of those receiving Paxlovid. Data from the initial EPIC-HR trial and recent real-world data also suggest they’re among the most likely to benefit from the oral antiviral, regardless of their COVID-19 vaccination status.
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“But at the same time, it unfortunately interacts with many very commonly prescribed cardiovascular medications and with many of them in a very clinically meaningful way, which may lead to serious adverse consequences,” senior author Sarju Ganatra, MD, said in an interview. “So, while it’s being prescribed with a good intention to help these people, we may actually end up doing more harm than good.
“We don’t want to deter people from getting their necessary COVID-19 treatment, which is excellent for the most part these days as an outpatient,” he added. “So, we felt the need to make a comprehensive list of cardiac medications and level of interactions with Paxlovid and also to help the clinicians and prescribers at the point of care to make the clinical decision of what modifications they may need to do.”
The paper, published online in the Journal of the American College of Cardiology, details drug-drug interactions with some 80 CV medications including statins, antihypertensive agents, heart failure therapies, and antiplatelet/anticoagulants.
It also includes a color-coded figure denoting whether a drug is safe to coadminister with Paxlovid, may potentially interact and require a dose adjustment or temporary discontinuation, or is contraindicated.
Among the commonly used blood thinners, for example, the paper notes that Paxlovid significantly increases drug levels of the direct oral anticoagulants (DOACs) apixaban, rivaroxaban, edoxaban, and dabigatran and, thus, increases the risk of bleeding.
“It can still be administered, if it’s necessary, but the dose of the DOAC either needs to be reduced or held depending on what they are getting it for, whether they’re getting it for pulmonary embolism or atrial fibrillation, and we adjust for all those things in the table in the paper,” said Dr. Ganatra, from Lahey Hospital and Medical Center, Burlington, Mass.
When the DOAC can’t be interrupted or dose adjusted, however, Paxlovid should not be given, the experts said. The antiviral is safe to use with enoxaparin, a low-molecular-weight heparin, but can increase or decrease levels of warfarin and should be used with close international normalized ratio monitoring.
For patients on antiplatelet agents, clinicians are advised to avoid prescribing nirmatrelvir/ritonavir to those on ticagrelor or clopidogrel unless the agents can be replaced by prasugrel.
Ritonavir – an inhibitor of cytochrome P 450 enzymes, particularly CYP3A4 – poses an increased risk of bleeding when given with ticagrelor, a CYP3A4 substrate, and decreases the active metabolite of clopidogrel, cutting its platelet inhibition by 20%. Although there’s a twofold decrease in the maximum concentration of prasugrel in patients on ritonavir, this does not affect its antiplatelet activity, the paper explains.
Among the lipid-lowering agents, experts suggested temporarily withholding atorvastatin, rosuvastatin, simvastatin, and lovastatin because of an increased risk for myopathy and liver toxicity but say that other statins, fibrates, ezetimibe, and the proprotein convertase subtilisin/kexin type 9 inhibitors evolocumab and alirocumab are safe to coadminister with Paxlovid.
While statins typically leave the body within hours, most of the antiarrhythmic drugs, except for sotalol, are not safe to give with Paxlovid, Dr. Ganatra said. It’s technically not feasible to hold these drugs because most have long half-lives, reaching about 100 days, for example, for amiodarone.
“It’s going to hang around in your system for a long time, so you don’t want to be falsely reassured that you’re holding the drug and it’s going to be fine to go back slowly,” he said. “You need to look for alternative therapies in those scenarios for COVID-19 treatment, which could be other antivirals, or a monoclonal antibody individualized to the patient’s risk.”
Although there’s limited clinical information regarding interaction-related adverse events with Paxlovid, the team used pharmacokinetics and pharmacodynamics data to provide the guidance. Serious adverse events are also well documented for ritonavir, which has been prescribed for years to treat HIV, Dr. Ganatra noted.
The Infectious Disease Society of America also published guidance on the management of potential drug interactions with Paxlovid in May and, earlier in October, the Food and Drug Administration updated its Paxlovid patient eligibility screening checklist.
Still, most prescribers are actually primary care physicians and even pharmacists, who may not be completely attuned, said Dr. Ganatra, who noted that some centers have started programs to help connect primary care physicians with their cardiology colleagues to check on CV drugs in their COVID-19 patients.
“We need to be thinking more broadly and at a system level where the hospital or health care system leverages the electronic health record systems,” he said. “Most of them are sophisticated enough to incorporate simple drug-drug interaction information, so if you try to prescribe someone Paxlovid and it’s a heart transplant patient who is on immunosuppressive therapy or a patient on a blood thinner, then it should give you a warning ... or at least give them a link to our paper or other valuable resources.
“If someone is on a blood thinner and the blood thinner level goes up by ninefold, we can only imagine what we would be dealing with,” Dr. Ganatra said. “So, these interactions should be taken very seriously and I think it’s worth the time and investment.”
The authors reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.